It is necessary that roadways and bridges be built of sections of slabs with an expansion gap between adjacent slabs to accommodate for environmental changes in temperature and vehicular traffic. Generally, the slabs expand with increasing temperatures and contract with decreasing temperatures. Furthermore, the slabs must be capable of moving vertically to accommodate for vehicular traffic.
A durable, yet flexible joint between the slabs is desirable. Additionally, a flexible joint which is waterproof is warranted to prevent water from getting under the slabs and rusting the bridges. A waterproof joint is also desirable to keep various corrosives such as roadway salt, fuel, oil, etc. from passing through the joint.
Various expansion joints are known in the art. One disadvantage of many prior art expansion joints is that they are typically recessed somewhat from the abutting surfaces so that when a vehicle passes thereover, a slight dip is felt. Dirt and debris fill the recess of the joint and accelerate deterioration of the joint. If the joint becomes unsealed at any juncture the dirt and debris become lodged in that unsealed portion and further tear the joint apart. The joint quickly degenerates as more dirt and debris become lodged in the unsealed portions of the joint.
Another disadvantage of many prior art expansion joints is that the material used to fill the gap of the joint must be able to bond to the adjacent slabs in some way. Typically, a recess is cut into the adjacent slabs and filled with particular materials capable of bonding to the gap-filling material. However, such recess-filling materials are limited in number because of the requirement of having to be able to bond to the gap-filling material. Furthermore, expansion and contraction of the joint often weakens the bond between the gap-filling material and the recess-filling material so that the bond breaks and separation between the two materials occurs. These prior art expansion joints therefore do not have a long-lasting life, but must be repaired and/or replaced frequently.
Accordingly, it is a primary objective of this invention to produce an expansion joint that is not recessed from the abutting surfaces, but is at a generally even grade therewith. This will prevent dirt and debris from accelerating deterioration of the joint, thereby resulting in a long-lasting, cost-effective expansion joint.
It is yet another object of this invention to produce an expansion joint comprised of a homogenous material throughout the joint to eliminate the bonding difficulties present in the prior art expansion joints. It is still yet another object of this invention to provide a method for producing an expansion joint, quickly and economically.